Wankel engine

Wankel engine, internal-combustion engine that produces rotary motion directly. Invented by the German engineer Felix Wankel, who completed his first design in 1954, it is used in automobiles and airplanes. A triangular rotor with spring-loaded sealing plates at its apexes rotates eccentrically inside a cylinder, while the 3 combustion chambers formed between the sides of the rotor and the walls of the cylinder successively draw in, compress, and ignite a fuel-and-air mixture. The Wankel engine is simpler in principle, more efficient, and more powerful weight-for-weight than a conventional reciprocating engine, but it is more difficult to cool.

See also: Internal combustion engine.